This invention generally relates to loading, unloading and transporting bulk commodities in cargo containers; and more particularly, to bulkheads for such containers and to methods, and to lining systems especially well-suited for use in those methods, to help control the atmospheres in cargo containers.
Bulk cargo, such as grain, may be loaded into large containers and then transported in those containers from one location to another by ship, truck, or railroad, or some combination thereof; and once the containers reach a final destination, various techniques may be employed to unload the cargo from the containers. For instance, a low pressure, or suction, line may be connected to an opening in the back of a container to draw the cargo out of the container, or the container may be tilted so that gravity forces the cargo through the back of the container. While these unloading processes generally operate relatively effectively, it is believed that they may be improved upon in several respects.
For example, with these unloading procedures, the bulk cargo generally is forced backwards, toward the rear of the container, but is not directed in any significant way specifically toward the outlet in the back of the container; and the unloading process would be more efficient if the cargo was specifically directed, as it moves rearward through the container, toward the back outlet thereof. Also, as the cargo is unloaded, an appreciable amount of the cargo may collect in the lower left and lower right hand corners of the back of the container, and often it is necessary to have a worker make a special effort to remove the portion of the cargo that collects in these corners. This is expensive and time consuming, and hence the unloading process could be improved by reducing the amount of cargo that collects in those back corners of the container.
In addition to the foregoing, many bulk commodities such as coffee and cocoa beans, rice and sugar, are shipped over very large distances from regions of the world where the commodities are grown to regions where they are processed or consumed. Typically the environment in which the commodities are located while being shipped is not closely controlled, and the shipments may be subjected to wide changes in temperature and humidity. Further, the shipments normally are not well ventilated and often gases which are produced by the commodities, will accumulate in the cargo containers.
For example, as a cargo container is shipped from a tropical climate to a temperate zone, the temperature of the container may drop over 100.degree. F., and this may cause moisture to condense in the container. This moisture, in turn, may be absorbed by the goods in the container and cause fungus and bacteria to grow in those goods. Further, several agricultural products, such as coffee and cocoa beans, ferment as they are transported and produce gases in the cargo container. Normally, the air in which the commodities are stored is not well ventilated, and gases produced by the commodities accumulate in the air in which the goods are held. If this happens, moisture in the gases may condense and be absorbed by the goods, causing fungus and bacteria to grow in those commodities.